The Impacts Of Typical Antibiotics On Wastewater Treatment Processes And Their Methanisms

The abuse of antibiotics in human and animals has been seriously concerned resulted in a series of environmental pollution.Part of the used antibiotics entered into the wastewater treatment plants via urban sewage system and surface runoff.In this study,the impacts of typical antibiotics on the performances of nitrificaiton-denitrification process and single-stage partial nitrificaiton-anammox process and their removal during the processes were investigated.The following conclusions were obtained:(1)The start-up of nitrificaiton-denitrification process and single-stage partial nitrificaiton-anammox process in the sequencing batch reactors(SBRs)was investigated.After 20 days' operation,the COD and NH4+-N removal efficiency in three SBRs were eventually reached around 95%.In the effluent of each reactor,nitrite was barely detected and a small amount of nitrate was found.These results indicated that the start-up of nitrificaiton-denitrification process was achieved in the reactor.The start-up of single-stage partial nitrificaiton-anammox process in the SBRs was also investigated.Results showed partial nitrificaiton and anammox was successful coupled together at with the nitrogen loading rate(NLR)less than 168 g-N m-3 d-1.The removal efficiency of NH4+-N and total nitrogen reached to 98% and 80%,respectively.However,when the NLR reached 168 g-N m-3 d-1,the single-stage partial nitrificaiton-anammox process was shocked.As a result,the removal efficiency of NH4+-N and total nitrogen declined by 8% and 20%,respectively.(2)The impacts of arsanilic acid and amprolium hydrochloride on nitrificaiton-denitrification process was investigated.The COD removal and nitrification were affected when the concentration of ASA or AMP reached 100 mg L-1.The removal efficiency of COD and NH4+-N decreased by 8% and 20%,respectively.The inhibition to COD removal was reversible whereas the inhibition to nitrification was irreversible.Phosphate removal was not affected by the continuous exposure to ASA or AMP.AMP was very resistant to be degraded by the activated sludge in the SBRs while a small amount of ASA was degraded into inorganic arsenic.16 S rDNA sequence results indicated that microbial community and bacterial diversity were influenced by the exposure to 100 mg L-1 ASA.(3)The impacts of sulfaquinoxaline sodium,oxytetracycline and arsanilic acid on single-stage partial nitrificaiton-anammox process was investigated.The partial nitrification and anammox in the reactor as influenced by dosing each 5.0 mg L-1 SQ-Na,OTC and ASA,and the inhibition to partial nitrification was irreversible.The removal efficiency of NH4+-N and total nitrogen decreased by 8% and 20%,respectively.The activity of nitrite oxidizing bacteria in the reactor was gradually recover when ammonia oxidizing bacteria and anammox bacteria was inhibited by 5 mg L-1 of SQ-Na,OTC and ASA,causing an increase of the nitrate concentration(6 mg L-1)in the effluent.SQ-Na,OTC and ASA could not be effectively biodegraded in the single-stage partial nitrificaiton-anammox process.